The present invention generally relates to electrical switching and more particularly to an electronic switching apparatus for electric guitars.
The quality electric guitar typically will have three pickups placed under six metal strings for transforming the mechanical vibrations of the metal strings into proportional analog signals. Each of the pickups are typically composed of a single coil of wire having two wires connectable to a guitar output circuit consisting of a shielded two conductor cable, which, in turn, is connected to an an audio amplifying device. The pickups are normally connected in parallel so that their analog signals are added together. The analog signals from the pickups are then amplified and projected at the audience via the audio amplifying device and speakers.
The pickup nearest to the string anchor of the electric guitar will only be able to pickup the high frequency components of the mechanical vibrations of the metal strings because the amplitude of the mechanical vibrations of the metal strings is reduced the closer a pickup is to the string anchor. The pickup furthest from the string anchor will, therefore, be able to pickup more of the low frequency components of the mechanical vibrations of the metal strings. The pickup located midway between the other two pickups will be able to pickup more of the midrange components of the mechanical vibrations of the metal strings.
Since each of the pickups are better able to pickup different frequency components of the mechanical vibrations of the metal strings, the musician frequently wishes to electrically switch in and out certain combinations of all of the pickups in order to produce different musical effects. This electrical switching must be done (1) quickly while playing the electric guitar, (2) substantially quietly (in an electrical noise sense) and (3) accurately so that the switching of the chosen combination of all of the pickups is visually and audibly unnoticeable to the audience.
Traditionally, a single one pole, 3-position switch is provided on electric guitars. This allows selection of one of three pickups, or, if the switch detents are defeated or altered, adjacent pairs of adjacent contacts may be bridged allowing selection of two pickups, namely 1 and 2, or 2 and 3. Combinations 1 and 3, and 1, 2, 3 (also all pickups off) are not available ordinarily, unless the guitar is rewired to accept three discrete ON/OFF switches (whose disadvantages are elaborated above.)
Prior to the present invention, the electric guitar has, in some cases, been provided with discrete switches, one for each pickup. Each of these discrete switches are hard wired into the pickup wiring and, in fact, are electrically connected in series with the wires coming from each of the pickups so that by manually flipping one of these switches, the musician can electrically switch one of the pickups in or out of the guitar output circuit.
There have been several very noticeable disadvantages inherent in these discrete hard wired switches. First, the switching of a chosen combination of pickups takes too much time because at many as three switches would have to be switched in order to obtain the desired combination of pickups. Second, because the musician is usually focusing his attention primarily on playing the metal strings, he is likely to throw the wrong switches when trying to switch in a desired combination, and, thus is often unable to obtain the desired musical effect during his performance. Third, the hard wired discrete switches place a very noticeble "click" (electrical transient signal) into the guitar output circuit each time a switch is switched ON or OFF. The audience is thus annoyed by loud "clicks" each time the musician wishes to change the combination of pickups. Fourth, the musician appears awkward and loses the continuity of his visual presentation when he is taking time out to clumsily switch three discrete switches several times during each song.
The same disadvantages described above as well as time delay also apply to the standard three or five position switches when switching from one extreme position to the opposite. Transients can occur when each switch position is passed.
The present invention has, to a great extent, done away with the disadvantages of the discrete hard wired switches by inventing an electronic switching apparatus which offers a single switch for each possible combination or a selection of combinations of pickups switched in and out of the guitar output circuit. In addition, the switching of the desired combination of pickups is also substantially free of electrical noise.